I think there a fairly good chance that the pornographic images will put you into a mental state where you can't effectively concentrate on Anki reviews.
When I tried this, the images failed to arouse me and just got annoying. If you successfully created a fetish for anki reviews (or mathematical symbols, or reading carefully-reasoned arguments, or destroying ugh fields...), I don't actually think that would interfere much with the task, especially if you were able to abstain from sex/masturbation for a long time (perhaps through some sort of precommitment mechanism, such as a chastity belt with the key either given to someone else with instructions not to give it back for some time, or stored three hours' ...
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.